The present invention relates to driving a carriage, the carriage carrying a print head in a printer, particularly a matrix printer, under utilization of a drive motor, and of a cable to which the carriage is attached and which is run through a driven drum pulley or sheave being journalled in stationary fashion. The cable being looped has several loops around the drum and is run around a deflection pulley disposed on the opposite side of the printer frame and returned, so to speak, to the other side of the carriage.
Drives of the type to which the invention pertains are usually controlled through a clocking or timing circuit, wherein a control is provided using increments of the travel path as controlling units. These increments are, for example, represented by a slotted disk, and a scanner produces rectangular signals as the slotted disk rotates commensurate with the carriage propagation. These signals for pulses progressively indicate the propagation of the head past the printing platen. The pulses are then used, for example, to control a step motor or DC motor.
Printers, particularly matrix printers, which are manufactured in large numbers, often use differently heavy print heads to be combined with the drive mechanism. For economic reasons and mass production the same kind of drive mechanism should be used for different heads. Therefore, the drive has to be configured so that at least small differences in the weight among the various heads can easily be compensated for.